Maiz N, Kagan K O, Milovanovic Z, Celik E, Nicolaides K H
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital, London, UK.
Ultrasound Obstet Gynecol. 2008 May;31(5):503-6. doi: 10.1002/uog.5282.
To determine the number of scans necessary for training sonographers to examine accurately the ductus venosus at 11 + 0 to 13 + 6 weeks' gestation.
Ten sonographers with prior extensive experience in the measurement of nuchal translucency thickness were given practical training in the accurate assessment of the ductus venosus. They were then asked to examine the ductus venosus during the routine 11 + 0 to 13 + 6 weeks' scan. Each scan was assessed by an experienced sonographer and classified as being successful or unsuccessful (failure to obtain a waveform, poor quality image with contamination or wrong classification of the A-wave). Each sonographer performed a total of 300 examinations, the data were analyzed in 15 groups of 20 examinations and in each group the percentage of unsuccessful examinations was calculated.
In the total 3000 cases examined by the 10 sonographers there were 2849 (95.0%) successful examinations and 151 unsuccessful, including 104 failures to obtain a waveform, 30 cases where the quality of the image was considered to be inadequate and 17 cases in which the classification of the A-wave was wrong. The overall frequency of unsuccessful examinations decreased significantly with the number of scans carried out (r = 0.982, P < 0.0001). The sonographers required an average of 80 examinations before they could successfully examine the ductus in at least 19 of a group of 20 scans. Although one of the 10 trainees achieved this standard within the first block of 20 scans some of the sonographers required training in 100 cases.
Competence in Doppler assessment of the ductus venosus is achieved only after extensive supervised training.
确定为使超声检查医师在妊娠11⁺⁰至13⁺⁶周时能准确检查静脉导管，所需的扫描次数。
对10名先前在测量颈项透明层厚度方面有丰富经验的超声检查医师进行准确评估静脉导管的实践培训。然后要求他们在妊娠11⁺⁰至13⁺⁶周的常规扫描中检查静脉导管。每次扫描由一名经验丰富的超声检查医师进行评估，并分为成功或不成功（未能获得波形、图像质量差有干扰或A波分类错误）。每名超声检查医师共进行300次检查，数据按20次检查一组分为15组进行分析，并计算每组不成功检查的百分比。
在10名超声检查医师检查的总共3000例病例中，有2849例（95.0%）检查成功，151例不成功，其中104例未能获得波形，30例图像质量被认为不合格，17例A波分类错误。不成功检查的总体频率随着进行的扫描次数显著降低（r = 0.982，P < 0.0001）。超声检查医师平均需要80次检查才能在一组20次扫描中至少有19次成功检查静脉导管。虽然10名受训者中有1名在最初的20次扫描组内达到了这一标准，但一些超声检查医师需要100例的培训。
只有经过广泛的监督培训才能掌握静脉导管的多普勒评估能力。
